JPH0597967A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition, containing a specific phenolic resin and an epoxy resin in a prescribed proportion, having a low elastic modulus, linear expansion coefficient and water absorptivity and excellent in heat and solder crack resistance. CONSTITUTION:The objective composition containing (A) a phenolic resin expressed by the formula [(n) is >=0; R is alkyl; X1 and X2 are halogen or hydrogen] and (B) an epoxy resin prepared by epoxidizing the phenolic resin with an epihalohydrin, etc. Both components are contained in amounts of 0.5-1.5mol hydroxyl group in the component (A) based on 1mol epoxy groups in the epoxy resin. The composition is suitable as a sealing material for semiconductors.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an epoxy resin composition. More specifically, it relates to an epoxy resin composition having a low elastic modulus, a low coefficient of linear expansion and a low water absorption, and excellent heat resistance and solder crack resistance.

[0002]

2. Description of the Related Art Conventionally, diodes, transistors, I
As a method of sealing a semiconductor element such as C or LSI, a so-called resin sealing method using an epoxy resin or the like is widely used. In particular, a resin composition containing an epoxy resin or a novolac type phenol resin as a main component is inexpensive as a raw material,
Due to its excellent heat resistance, moldability, and electrical characteristics, it has become the mainstream of resin encapsulation methods.

By the way, the recent progress in semiconductor element-related technology is extremely fast and diversified, and the conventional epoxy resin or novolac type phenol resin-based resin composition is used as a sealing material. There are various problems that cannot be solved by the method.

[0004] For example, the chip size is increased with the high integration of ICs, and conversely, the package shape tends to be smaller and thinner due to further expansion of surface mounting. That is, it becomes necessary to encapsulate a large chip in a small and thin package, and at this time, thermal stress causes cracks, which is a serious problem.

Further, in the soldering process, the package itself is rapidly exposed to a high temperature of 200 ° C. or more, so that the moisture in the package is rapidly expanded and a crack is generated in the package to improve the reliability of the semiconductor. It is causing the decrease.

Various epoxy compositions have been proposed in order to solve these problems, but sufficient effects have not been obtained yet.

For example, JP-A-59-105018 proposes a sealing resin composition using a polycondensation product of phenol and aralkyl ether as a curing agent. However, although this resin composition is excellent in terms of low water absorption and low elastic modulus, it has poor heat resistance due to its low glass transition temperature and is not satisfactory in terms of solder crack resistance.

Further, JP-A-61-168620 proposes an epoxy resin composition having excellent heat resistance. Since the composition uses a polyfunctional epoxy resin, the crosslink density is increased and the heat resistance is excellent. But,
The water absorption is high, and the frequency of cracks is particularly high in the soldering process, which is not satisfactory.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and the elastic modulus, linear expansion coefficient and water absorption coefficient are low, and the heat resistance and solder crack resistance are excellent. An object is to provide an epoxy resin composition.

[0010]

DISCLOSURE OF THE INVENTION The present inventors have found that a phenolic resin and an epoxy resin composition containing an epoxy resin obtained by epoxidizing the phenolic resin as an essential component solve the above problems. That is, the present invention has been achieved.

That is, the present invention has the general formula (1)

[0012]

[Chemical 2] (In the formula, n represents an integer of 0 or more, R represents an alkyl group, X represents
₁ , X ₂ represents a halogen atom or a hydrogen atom), and a resin composition containing an epoxy resin obtained by epoxidizing the phenolic resin as an essential component. The hydroxyl group of the phenolic resin is 0.5 with respect to 1 mol of the epoxy group.
It is an epoxy resin composition which is about 1.5 mol.

The greatest feature of the epoxy resin composition of the present invention is that it has a low elastic modulus, a linear expansion coefficient and a water absorption coefficient, and also has excellent heat resistance. All of these characteristics are extremely important as an epoxy resin composition for semiconductor encapsulation, and an epoxy resin composition having all of these characteristics has hitherto not been known. This is possible for the first time by using a phenolic resin and an epoxy resin containing an epoxy resin obtained by epoxidizing the phenolic resin as an essential component.

The epoxy resin composition of the present invention contains a phenolic resin represented by the above general formula (1) and an epoxy resin obtained by epoxidizing the phenolic resin as essential components, but other phenols. Resins, other epoxy resins, curing accelerators, various fillers and the like may be added as long as the object of the present invention is not impaired.

The method for producing the phenolic resin used in the present invention is represented by the general formula (2)

[0016]

[Chemical 3] (In the formula, R ₁ and R ₂ each independently represent a hydroxyl group, a halogen atom or a lower alkoxy group having 1 to 3 carbon atoms, and X ₁
And X ₂ each independently represent a hydrogen atom or a halogen atom. ) And a substituted phenolic compound are subjected to a polycondensation reaction (crosslinking reaction).

Examples of the bifunctional aromatic compound represented by the above general formula (2) include α, α'-dichloroxylene, α,
Examples include α, α′-dihaloxylene such as α′-dibromoxylene, α, α′-dialkoxyxylene such as α, α′-diethoxyxylene, xylylene glycol and the like. These compounds may be in the ortho, meta or para form. Also,
These compounds may be used alone, or may be used as a mixture of two or more kinds, and may be a compound in which a halogen atom such as fluorine, chlorine, bromine or iodine is bonded to the aromatic nucleus of the above compound. ..

The substituted phenolic compounds include cresol, ethylphenol, propylphenol, tert.
-Butylphenol, sec-butylphenol, phenylphenol and the like can be mentioned. These compounds may be in the ortho, meta or para form. Further, these compounds may be used alone or as a mixture of two or more kinds, and the molar ratio of the substituted phenolic compound to the bifunctional aromatic compound is 1.2 to 20, preferably 1.3. ~ 15. If the molar ratio is less than 1.2,
The cross-linking reaction proceeds too much, and a high molecular weight polymer having a number average molecular weight of more than 2000 tends to be formed, which may cause gelation. On the other hand, when the molar ratio exceeds 20, the heat resistance decreases and the object of the present invention cannot be achieved.

The above crosslinking reaction is preferably carried out in the presence of an acidic catalyst. However, in the case of α, α′-dihaloxylene, the crosslinking reaction may proceed even without a catalyst.

Examples of acidic catalysts are hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, oxalic acid, zinc chloride, aluminum chloride, stannous chloride, ferric chloride, boron trifluoride, cupric chloride, and sulfuric acid second. Copper, silver sulfate, sodium hydrogensulfate, methanesulfonic acid, p-toluenesulfonic acid, and 1 to 10 carbon atoms
Examples thereof include dialkyl sulfuric acid having 6 alkyl groups.

Examples of the dialkyl sulfuric acid include dimethyl sulfuric acid, diethyl sulfuric acid and diisopropyl sulfuric acid. These acidic catalysts may be used alone or as a mixture of two or more kinds.

The amount of the acidic catalyst used is not particularly limited,
It is preferably 0.0001 to 10% by weight based on the total amount of the bifunctional aromatic compound and the substituted phenolic compound.

The temperature of the crosslinking reaction is usually 50 to 250 ° C., preferably 70 to 200 ° C., and the reaction time is generally several minutes to 100 hours.

It is extremely preferable to discharge hydrogen halide, lower alcohol, water and the like produced as the reaction progresses out of the system.

After completion of the reaction, excess substituted phenolic compound is removed by vacuum distillation or the like, if necessary, to obtain a phenolic resin used in the present invention.

In the phenolic resin, n in the above general formula (1) is an integer of 0 or more, and it is preferably 0 to 20 for the purpose of the present invention.

The epoxy resin used in the present invention is obtained by epoxidizing the above phenolic resin.
A known method can be applied to the epoxidation method. That is, in the presence of a hydrogen halide acceptor, 40-12
In the temperature range of 0 ° C., the phenolic resin is epoxidized with epihalohydrin, preferably epichlorohydrin.

Examples of hydrogen halide acceptors include alkali metal hydroxides such as potassium hydroxide and sodium hydroxide. The hydrogen halide acceptor is preferably added slowly to the heated mixture of phenolic resin and epihalohydrin to maintain the pH of the reaction mixture at about 6.5-10.

The proportion of epihalohydrin used in the epoxidation reaction depends on the OH group content of the phenolic resin, but is usually 2.0 to 30 equivalents per 1 equivalent of the OH groups,
An excess of epihalohydrin, preferably 2.0 to 10 equivalents, is used. The method of removing the excess acceptor substance and the by-produced salt from the reaction product is usually carried out by a means such as washing with water.

As described above, the epoxy resin used in the present invention can be used in the presence of a hydrogen halide acceptor.
An epoxy resin (hereinafter referred to as an essential epoxy resin) obtained by epoxidizing the phenolic resin represented by the general formula (1) with epihalohydrin. In addition to this, a novolac resin and a dicyclopentadiene-modified phenol resin , Glycidyl ethers such as resole phenolic resins, glycidyl ethers of alcohols such as butanediol, polyethylene glycol, polypropylene glycol, glycidyl esters of carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, aniline, isocyanuric It is also possible to use in combination an active hydrogen bonded to a nitrogen atom of an acid or the like with a glycidyl group, an alicyclic epoxy resin in which an intramolecular olefin is epoxidized (hereinafter referred to as a combined epoxy resin).

The amount of the combined epoxy resin used is preferably less than 50% by weight based on the total amount of the essential epoxy resin and the combined epoxy resin. When the content is 50% by weight or more, the above-mentioned characteristics, which are the greatest feature of the epoxy resin composition of the present invention, that is, the elastic modulus, the linear expansion coefficient and the water absorption rate are low, and the heat resistance is excellent can be maintained. It is not preferable because it disappears.

In the present invention, the phenolic resin represented by the above general formula (1) is used as a curing agent. In addition, novolac resin, dicyclopentadiene-modified phenolic resin, resole phenolic resin, etc. It is also possible to use a combined use phenol resin).

The amount of these combined phenol resins that may be used is preferably less than 50% by weight based on the total amount of the phenol resin and the combined phenol resin which are the constituents of the present invention. When the content is 50% by weight or more, the epoxy resin composition of the present invention has the above-mentioned characteristics that are the greatest features, namely, the elastic modulus, the linear expansion coefficient and the water absorption rate are low, and
It is not preferable because the property of excellent heat resistance cannot be maintained.

The softening point of these combined phenol resins is 6
The range of 0 to 120 ° C and the OH group equivalent of 90 to 500 are preferable, and the softening point is more preferably 65 to 100 ° C and OH.
The base equivalent is in the range of 95 to 400. Softening point or OH
When the base equivalent is out of the above range, the above-mentioned characteristics which are characteristic of the epoxy resin composition of the present invention cannot be maintained, which is not preferable.

These combined phenol resins may be used alone or in the form of a mixture of two or more kinds.

The mixing ratio of the essential epoxy resin and the phenolic resin as the curing agent is 0.5 mol of the hydroxyl group of the phenolic resin to 1 mol of the epoxy group of the epoxy resin.
A range of up to 1.5 mol is preferred. Outside this range,
It is not preferable because the above-mentioned characteristics which are the characteristics of the epoxy resin composition of the present invention cannot be maintained.

When the combined epoxy resin and / or the combined phenol resin is used, the total hydroxyl group is 0.5 to 1.5 relative to 1 mol of the total epoxy group.
It is preferably in the molar range.

In the epoxy resin composition of the present invention, a compound which promotes the reaction between the epoxy group of the epoxy resin and the hydroxyl group of the phenol resin which is the curing agent resin can be used as the curing accelerator.

Examples of the curing accelerator include amines such as triethylamine, benzyldimethylamine, triethanolamine, tris (dimethylaminomethyl) phenol, triethylamine, triethylenetetramine, metaxylenediamine, and dimethylbenzylamine;
Methylimidazole, 2-ethylimidazole, 1,2
-Imidazoles such as methyl imidazole, 2-ethyl-4-methyl imidazole, 2-undecyl imidazole, 2 phenyl imidazole, triphenylphosphine, tributylphosphine, tricyclohexylphosphine, methyldiphenylphosphine, butylphenylphosphine, diphenylphosphine, phenyl Organic phosphines such as phosphine, octylphosphine, 1,2-bis (diphenylphosphino) methane, tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, 2-ethyl-4-
Examples thereof include tetraphenylboron salts such as methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate.

The amount added is 0.00 based on the epoxy resin.
1% to 5% by weight is preferred. Addition amount is 0.001
If it is less than 5% by weight, the reaction between the epoxy groups of the epoxy resin and the hydroxyl groups of the curing agent resin takes too long, which is not preferable. On the other hand, if it exceeds 5% by weight, the above-mentioned characteristics which are characteristic of the epoxy resin composition of the present invention cannot be maintained, which is not preferable.

Further, in the present invention, as an inorganic filler, crystalline silica, fused silica, alumina, clay, titanium white, zircon, boron, beryllia, magnesia, zirconia, forsterite, steatite, spinel,
One or more kinds of mullite, titania, barium sulfate, quartz glass, aluminum hydroxide, potassium titanate, silicon carbide, silicon nitride, alumina, glass fiber and the like can be blended.

Further, in the present invention, higher fatty acids, higher fatty acid metal salts, esters, natural waxes, synthetic waxes, acid amides, mold releasing agents such as paraffin, bromine compounds, antimony, phosphorus are added, if necessary. Flame retardant such as carbon black, colorant such as carbon black, silane coupling agent such as epoxysilane, aminosilane, vinylsilane, alkylsilane, organic titanate, and other additives such as flexibility-imparting agent Good.

As a general method for producing the epoxy resin composition of the present invention using the above-mentioned raw materials, a raw material mixture having a predetermined amount is thoroughly mixed with a mixer or the like, and then kneaded with a hot roll, an extruder or the like. Then, a method of cooling and pulverizing can be mentioned.

As a method for encapsulating a semiconductor using the epoxy resin composition of the present invention, a low-pressure transfer molding method is generally used, but injection molding, compression molding, casting, etc. may be adopted. You can also

The epoxy resin composition of the present invention obtained as described above has low elastic modulus, linear expansion coefficient and water absorption and has excellent heat resistance. It can be used as a laminated material or an adhesive.

[0046]

EXAMPLES The present invention will be described in more detail with reference to production examples, examples, comparative examples and test examples.

Production Example 1 In a reaction vessel equipped with a stirrer, a thermometer, a partial condenser, and a total condenser,
α, α'-dimethoxy-p-xylene 100 g (0.6
0 mol), 95.2 g (0.88 mol) of p-cresol and 0.10 g of diethyl sulfate were charged, and the cross-linking reaction was carried out with stirring while maintaining the mixed solution at about 140 ° C.
The methanol generated during the reaction was removed from the system through the vent port. After reacting for about 2 hours, unreacted p-cresol was removed by distillation under reduced pressure, and the resinous product remaining in the reactor was cooled to obtain a light red solid resin. The softening point (according to JIS K-2548) of this resin was 95 ° C. This resin is called resin A.

Production Example 2 50 g of Resin A obtained in Production Example 1 and 1 of epichlorohydrin
50 g was mixed and charged into a reaction vessel equipped with a stirrer, a thermometer, a Dean Stark azeotropic distillation trap, and a dropping funnel. The temperature of this mixture was raised to 115 to 119 ° C. with stirring, and then 64 g of 47% aqueous sodium hydroxide solution was added at the same temperature.
Was added dropwise over 2 hours, and the distilled water was continuously separated and collected,
The epichlorohydrin phase was returned to the reactor. After the dropping is completed, the reaction is completed by removing the distilled water. After this, excess epichlorohydrin was distilled under reduced pressure, the reaction product was dissolved in 200 g of methyl isobutyl ketone, sodium chloride and sodium hydroxide were filtered, and the solvent was distilled off under reduced pressure to obtain an essential epoxy resin. Epoxy equivalent is 265
The g / eq and softening point were 78 ° C. This resin is called resin B
And

Production Example 3 O-cresol (87 g, 0.80 mol) was used, except that
A phenolic resin was obtained in the same manner as in Production Example 1. The softening point of this resin was 93 ° C. This resin is called resin C. Production Example 4 An epoxy resin was obtained in the same manner as in Production Example 2 except that the resin C obtained in Production Example 3 was used. The epoxy equivalent of this resin is 2
It was 60 g / eq and the softening point was 76 ° C. This resin is called resin D.

Example 1 Resin A produced in Production Example 1 as a curing agent resin, resin B obtained in Production Example 2 as an epoxy resin, triphenylphosphine (hereinafter referred to as TPP) as a curing accelerator, and melted as a filler. Silica, carnauba wax as release agent,
Carbon black as a colorant and glycidoxypropyltrimethoxysilane as a coupling agent were blended in a weight ratio shown in [Table 1], and roll kneading was performed under conditions of a kneading temperature of 100 to 110 ° C. and a kneading time of 5 minutes. .. The sheet-shaped kneaded product was cooled and then pulverized to obtain an epoxy resin composition.

Next, the composition was added to 200 kg / cm ² , 1
A molded product having a predetermined shape was produced by compression molding at 70 ° C. for 5 minutes, and post-cured at 175 ° C. for 5 hours. The glass transition temperature, linear expansion coefficient, flexural modulus, and water absorption of the obtained molded product were evaluated.

Glass transition temperature (unit: ° C.): From the temperature-linear expansion curve of the molded product using a TMA apparatus manufactured by Rigaku Denki, the temperature at the bending point was taken as the glass transition temperature. The temperature was measured from room temperature to 250 ° C., and the temperature rising rate was 2 ° C./min.

Linear expansion coefficient (unit: × 10 ^-5 / ° C); the value from room temperature to the glass transition temperature was determined.

Flexural modulus (unit: kg / mm ² ); 4 mm × 127 mm × using Shimadzu autograph
A 10 mm molded product was tested at a test speed of 2 mm / min and a fulcrum distance of 64 mm.

Water absorption rate (unit:%); 50 mm × 50 mm
It was determined from the change in weight after boiling a molded product of × 2 mm at 100 ° C. for 24 hours. The obtained results are shown in [Table 1].

Examples 2 to 3 and Comparative Examples 1 to 2 Using the raw materials shown in [Table 1] respectively, molded articles were obtained in the same manner as in Example 1 and each property was evaluated in the same manner. The obtained results are shown in [Table 1].

[0057]

[Table 1]

Test Examples 1 to 3, Comparative Test Examples 1 to 2 The epoxy resin compositions prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were tableted and subjected to low pressure transfer molding.
Under conditions of 175 ° C., 70 kg / cm ² and 120 seconds, a 6 × 6 mm chip for a solder crack test is sealed in a 52p package, and a solder moisture resistance test is 3 mm × 6.
The mm chip was encapsulated in a 16p SOP package.

The sealed test element was subjected to the following solder crack test and solder moisture resistance test.

Solder crack test: The sealed test element was left in an environment of 85 ° C. and 85% RH for 72 hours, then immersed in a solder bath at 260 ° C. for 10 seconds, and external cracks were observed with a microscope. The number of cracked elements was counted.

Solder moisture resistance test: 8 sealed test elements
Leave for 72 hours in an environment of 5 ° C and 85% RH, then 2
After soaking in a solder bath at 60 ° C. for 10 seconds, a pressure cooker test (125 ° C., 100% RH) was performed to measure the time at which the circuit open defect rate was 50%. The test results are shown in [Table 2].

[0062]

[Table 2]

[0063]

The epoxy resin composition of the present invention has a low elastic modulus, a linear expansion coefficient and a water absorption coefficient, and also has excellent heat resistance. Furthermore, since it has excellent solder crack resistance and solder moisture resistance, it can be used as a semiconductor sealing material. Further, by utilizing the above characteristics, it can be used in a wide range of fields such as for paints, for lamination and for adhesives,
It is extremely useful in industry.

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Claims (1)

[Claims] 1. General formula (1) [Chemical formula 1] (In the formula, n represents an integer of 0 or more, R represents an alkyl group, X represents
₁ , X ₂ represents a halogen atom or a hydrogen atom), and a resin composition containing an epoxy resin obtained by epoxidizing the phenolic resin as an essential component. The hydroxyl group of the phenolic resin is 0.5 with respect to 1 mol of the epoxy group.
An epoxy resin composition of about 1.5 mol.